SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab3384a2e50249e2555d87d4ef65eb4144e5f8e95be8f32a7a74a30d643e3b8' 
  AND token = 'G/EqRjh4ZB2cGPRH4K9z/XGoyLw4C4NssOtUovFp/ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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