SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc70d69a53b33f752825350d8aece1bde1e42cfadd2a371dbcfdd5a1f27b7566' 
  AND token = '5HhMVbZ1iwZkjbJz806YcNwzMMtTkLRRWjCLtXRnIqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}