SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85118b1bf9ec1049f4c2c66d2e7c3b971486dac5be0d23925ad929374c3af848' 
  AND token = '91iVS3r8KvPQQliw7Fnzvk5qJXHCUVOrNG8qkxigmi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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