SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2fc6372df36aa1a04f27ddccd8aad9ac603d4a0956e5bda542f2c30397c4f0d' 
  AND token = 'YGxWWCOJFjHyLg/KLLTgvFme/miHWwcmJ1DmZDhx21s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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