SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a522f8add7dfaf6e7f61585c2741b8d41bdfb32c3d06dd6422d17b4945c97cd2' 
  AND token = 'Spg1p+hrYejbpYP3WgGYu93+NVCgv9umZDFVmBGcaBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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