SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e88046bda146ba4c2173171135d3e9dbe8082f8fa923e324e2ba82e50de2aac4' 
  AND token = 't7MevSuV5rpizD2YaSbV3NvKnia89PXZIMLW/OaV1jE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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