SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '790714fade4bd299452f08d4435bd54ed60f6faadc4c6e27bc4c6190c775d8a8' 
  AND token = '+T4XzIT6b6I9CBZwsn6Jz1GysIg8o0UPslc7tyVxfIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}