SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c198290865d5e7808252012ca3955fa376c441c1e97c14ae5cd5fb134c43d22' 
  AND token = 'prAgSDOZW4+8fjN3rBQtNGPQF2LYRPzxjmctjsuXyWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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