SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27927e75e2eb124cffd896dba2307d84c6ac808d323f88179387ec8d2df4034b' 
  AND token = '7g5uS13z49hsziX+mRClMCVbws4Vj4K0Ka3oGJlVqxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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