SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fd74e56ce0872dc3269e0f6cb6b1dc5e5216cc250b83b8501c9ec1f5a6e8ddb' 
  AND token = 'EGyzUvOST1c5CrWlTp45GBCaGlVeuLxUHAYVCGS6RR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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