SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f4a9a728d8b001d9a903edb34acd1d059de3360e74d7625efc2defb282e84a63' 
  AND token = 'dCQO0A7pd0Z+oyNPujozj0p4cWdaSAtZRbFR1boYvtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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