SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7104822ae62a992117d28652363c869dbcb9f133b50ac909dac171d3f76c7052' 
  AND token = 'ux+31AOseLb4wKiZ88S4iKLp4TL52hYBS2YG9iJhRVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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