SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7a9224f0e24a5b88f407377ee86d3cd7064a88c937244c931560e66cbc1bc65' 
  AND token = 'vtu/RE8Vcv5Ejjyyx42Yl6kV+lLoNiZgJnmwDrBK/lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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