SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b953d0ff04135f1917d84df4811c1efde5c0886460c0a27a81f5a4edd1778f3d' 
  AND token = 'jodpRnjQ1jiHZXJDcRhVt43CPIGoPvlDO1ynMEBwmhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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