SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3e57f3bdbe6e12a86abcf01472c415fd0e1167395e59456309bdc43ca75797e' 
  AND token = 'LQJJXYRJGnE8ddhY1olXTY7IXtbPyTMKUmVIs161A4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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