SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4e6ccd947a13955b4038ba5e9a67f38fece7fc423c3f5cae231c24f2cab9170' 
  AND token = 'r2ihlCvNcaUVZTvMQY/X5CQcURifrzML32cbrufvnxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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