SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db3a784faaddd0cc65ded482d57dfe43c504c1b8d596d2ad07bf7f8ed60b7d61' 
  AND token = 'YxFYsEZ4+bAlhTSChYDkchWZFEr9Gguop3dGhaFtTTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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