SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '28f245cc71aedfb16f0c11bbe814eac297079111808618f4d09b02f5d7a9a30d' 
  AND token = 'B+l0/K7j4BY2CcVJsxpey+zaJshCdSaD7BMdohK6qso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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