SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dd794bfd139266f0be827a22c5177b999e0d4627f0cd50c7e2c9619d1b19d8b' 
  AND token = 'flcJIjH16nPfO5g8CeHCF+kWwIqjUNG805OR2pN+G1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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