SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df3309a8ae54bb3aaaa77244590f60319e96af1a3967313a56c0981b91462ec' 
  AND token = 'oAiPQPoMboLegbaIS7/kGAiQ2mkICLpoFB6XIqAHSFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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