SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f182b37c284c59a748a0e84369be043d4c6b7cd17595ccdca784c0f1acc1d685' 
  AND token = '1/RXCkdjBMuvRM7OqzqfTpjzwL3TCe0EPTYsMHzhaFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}