SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85f772cbcbaf7b1760c0a5bfcf79330f81c92d81c03a39717ff67664564918a' 
  AND token = 'TNJn2l/HR+9G/aOHWmIvq3dKnzBWDOa7dBMdz/C0oUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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