SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ace64accc78497bf83d0197e332446f669ea8b2669d6147c9273532b7d40f707' 
  AND token = 'ANniPMM7E/XMTDAihzUbmBnplWUNtcVTe0gu0uBifp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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