SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d2475b6fd2fb0de8cbbbf0fdbed524bb57e993a75dd7638c3d95486efc914cc' 
  AND token = '0mWE8mm0RBCNvrt+1gzPs5/JkTpqQBjxml+3Uq88UVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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