SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c784a792094af55c4cc1648f2aef7ea5040238b81dc033d39f3a8073c7bb9a8d' 
  AND token = 'aiAgkdzbwdtY5nXEacMEg/CwUTmouY7rEQ4VSB2AdAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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