SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e0b3e45c1116c1bc16eda195474df44eac76a4a4b34a119252e68a5a80fb0a7' 
  AND token = 'cSjKf3rdCcFkAQwQPLd1rSkdyS/WQdetSmtm75S2Ppo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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