SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f6d90b7d0954681e54e7442ffe1327e9a93e2aeb33fe397a12e5b46c9d32b85' 
  AND token = 'mH2/b3ZHwi4ZR35+wqiqhfpC8z/1Gb7hJZLMho+3m8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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