SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5c8425d4445fc8595b1c5d0d89d502632810a5a0371432c25020b4501c32b6a' 
  AND token = 'BP0pJYNbx97Kgz7NANXZrQowhmJqZG9mVjJiOHo6Fkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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