SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd32bd683bcc6f14de319cdccae1a75b9a2e2082e70b8376147af674b0b2dc5af' 
  AND token = '+Kw71Q3T0MUYa5gqjSKJEf3vqGn86+2pvPbMb9ZmFr4=' 
  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"
    }
  }
}