SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e6ff17e2cf2c3db0818fff2743773c9d650f66e41eebe742b5e970bc800405bc' 
  AND token = 'n+ApEhdqb1IdwrvwQDGmFDYkwpcsTz9SiihrYjSfqtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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