SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64a45cf41f95e325f8f27c1f7fe29f6e1bb095c2c43ff8aeb9ff7499483a6254' 
  AND token = 'cT0w+kvr8IdDgzr23ovemOPgR0KSVbXI8ZgSdXpn1vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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