SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d2a7909de0bfee499a9e2326455d0e83e45cf8fd8816638783f70608166ef06' 
  AND token = 'udas6wGbqJ/Vi6X5qKymh2bDajq1XaBGmiXfkFmHFuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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