SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a850427356e549239f6b3060aab84f67e266cf28dec991c5f2ec4e82311f425' 
  AND token = 'LSCKpgR8pi+QbzBbo3NMOgA/q4gJfz5Mx6H7NrZz3FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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