SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e921eec0fcadb8c4eea9832165dded1de3f1270daf2feb00dcc6905e9bdecb0e' 
  AND token = 'MXvNO4ZohCGhJOFY8L+DIdeoOgEgXrypH2pfmZJsRFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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