SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f6c76f98a4fd87b9f7a54d195267529db91486d431d3f6d413f4daaed5627d6' 
  AND token = '5vKaoWLq5hHjyFieRMwd93/opqGVFUzAPkwGlrtnMOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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