SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e68a7347be8c0420c52cfd5d43d1fc893e64fabbdac48a0dec556f37b65c3224' 
  AND token = 'jTkRh2Jk80qoOjtusLqmVHZ299Wx2+vVUpo/QjyA1Nc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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