SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2bfe96f4ff2ffbfccff4e2511a37730a59d4b5390433ef2ddbf3f9781511ebd' 
  AND token = 'w2xxBFS7L+O0UzECawtU+Wh43ZiGXe8QW3tZwF/Bujk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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