SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a277dbd29d959765d032f9aacfbcaee0c5e0184715e2968be582d3fcb1792d42' 
  AND token = 'ziL2+64udDRXrfVE2JJt2GgCllDXJG8KI/w34p3Y/2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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