SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '186069b2e139ccf9cf033303e78a1d3bb950c776801ce63d0115a93a0763dbd2' 
  AND token = 'BZMX3MfjHeYheMKmBuvFzZewJiy1wx5u5RDqnMdGCdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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