SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84bdb3c91e1617441cf2aeaf19473b32981124bd90fa0df2c6be1711fbb657d5' 
  AND token = 'zXxxGJu61uwrJFza5QNXtCrUq+XJb+wubj3spjPyrLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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