SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62052e8a7e3748075c0cb4021186a3f4fbc9996cb1c0222e2782a8aa190fffea' 
  AND token = '6KssBQ+bL+6bXrVhltLyerRSriSAnwWg7HVwnGhZubY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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