SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fac307c5ab29f8f644d68eacc0d7ee2aaee0e31a99ac38ff10c7d7ede1588b23' 
  AND token = 'ajI1nnVpB6Zi01Gej9ex4cn/v0304OJolcHVBKvPpuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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