SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c014a12f6ca8b410543cb32f2c61cdc2f3138e2a65ba7c01e795f8735ad431e3' 
  AND token = 'aI/ewNYFlfC17BF1tl2dIgEEacN0KJbSUtd43ePpmoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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