SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d4617ce32c5596dada797aa70950089ffbe5cd60f53f147be167cecdffa5cd3' 
  AND token = 'myR+zr5bcoHKjBTs5Pc7FqtWKEP5BSI4AL09ZVIrTqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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