SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b711d256767b646660f263cb78dddb020c4f5a6b641950dd6175e0234aa0ade' 
  AND token = 'n2wND1lWjb+CYMHjzBgdfQZqTnTvVtCbGvRSc4hEyeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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