SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78c1df9d5e4ed49e1aca73350e76b134b2ec19877889ffb1598c8997487945d' 
  AND token = 'QmQjQcRgmDN1awrLg0EnavXJ3KyWSVbSOa+MkQqNXtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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