SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ed76286223232c0edd642183174bbeab6e8ed5335362ccf59fe757f34b9cf9d' 
  AND token = 'LOLM3uj9x2RggpuVzYp+sRa+vSXXTv1WExBZq2dqLtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}