SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b88fa2772eb91c6a572f8e8628cc4135604a77832b57924daf94b442b5e02ce' 
  AND token = 'phLCDZjC5E0KQ3GXi+Lvg8AUEbHE3+GRn+EXH/92mIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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