SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f8c038bc09c4ffee0696b0161ab383d82bbc879014c541c6986e2d0df974094' 
  AND token = 'JaCrQcjs6IHnS1ioy8dqcpeGSjPKHcQ2sEFNwy3XSqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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