SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eb5b4a6b229b4ec32cb642dbb3402da60f6dc20d29d92179b197d21a347af86' 
  AND token = 'N7vMKqgFdPh4HBP3vxRcY1HlmypaOWPlpw+59GWh+Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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