SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fc394478e219c16efe20e884fdd7a1ca6f80258e548e61acfabcb781a4af6cf' 
  AND token = 'JjWfn91Cf1ZvsnvcGQLV1Sl1+durbpAWL8VZMZO3E3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}