SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca8a2842e042b87dbba30f5e7a26ec939b7ee75b4a0e76dcb8fd65e7743c17e6' 
  AND token = 'LfAA+HiUtdxkqwlAALRZ+JQtJA8KQ+QFzOPaNlcHsEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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