SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53861c6b010d735540a0928da4f51d79e200c9477b383d2c57bd9524a50264a4' 
  AND token = 'xl+KpKyxdwfZtHlVlPDzjnhhvE/rifaHCoao9Qaf5Wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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