SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8960a79dbbd88eb34d4226caaf0def23a85567ab6b135ba0a2517a5bd422e74c' 
  AND token = '6sdjJN/iG/3n5l++PAR4YvamBRaSCtPhk3RccEBIafE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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