SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977b11c21b065462a1895b61980097011404ce19824c4152bebf3c88c1b06b40' 
  AND token = 'r0LmWyi/7JUzUZTk+omJudnMqXNzS5+GadFbcvOaQ8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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