SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20885ffeaa45ba1f733d204446ef6ca10c217213f8d9f87364f8a313c06473f8' 
  AND token = '9hKkumcREHqJvkQC/UO+nh2vgXGYN12lChjisG7xKqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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