SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e29751f277217860151bd98c23bb6dfac344f887db8d3e60271077c38b0512' 
  AND token = 'KVng/zEYaiWyxUn9HiCMc0PAuzTaHgwZM2UWQDvS5Ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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