SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a362f94ce32fb0d67bf9481affad1f2c05a5a8208c329ab7e27b1e745e695c9' 
  AND token = 'nU/LZMhpdvGdq1vrl3AfuiHl5YDCYmHkFDMudqPBi+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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