SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd752436b52181ceffe13ff5334ed4e3a172436797365f208506d521020b3ec6e' 
  AND token = 'UgAEm+ilBlmJ3Ud3jDTRvXKBtDHQmuWXJJLEq+TI6ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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