SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e3d93c65d81681a7c26048a650167747fb54ea944619b8622dafaecd3c03808' 
  AND token = '0oad3b4rTcFKBp7355smhcRTm1TwDoTnVyYYgtFg7HA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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